Best Starfields in Demos, or games?

[Neild323]

I'm looking for a good PRG which could hopefully allow me to control a starfield.
I've seen a few on various demos which allow me to control certain parameters like speed & direction etc, but haven't found one suitable for this purpose yet. Sometimes I see great starfields but they are displayed too briefly to use.

I'm wanting to screen capture the starfield to later add a sprite I made in 'pixel-edit', so I'll be animating this sprite in final cut as I"m familiar with the software.

Ideally I'd create my own starfield. It's the longest way around it but I figured I'd learn to write in STOS basic as I'd also like to make some scrollers for my visuals (through steem for now), but I've been finding a few issues getting started (mainly trying to enter language disk 1 to learn throught the manual's guide), so I'm coming back to my original purpose to find an easier way whilst I take more time to understand A drives in steem & STOS. I've searched a lot for good starfield PRGs, or games which display them well enough to record as I'm spending too much time fault finding in order to load up code of a starfield setup in STOS which I'd like to further edit.

Any recommendations for a cool starfield, or a starfield editor as such would be great if anything springs to mind.
Cheers Atari heads!

[LynXX]

If I remember correctly Demo Construction Kit has a starfield making tool allowing you adjust a lot of parameters.

There seem to be a tutorial in English there: http://www.atari-wiki.com/index.php?tit ... ction=edit

[mlynn1974]

There are some nice starfields in demos by The Lost Boys.
The maths isn't too difficult and can easily be implemented in STOS.

I seem to remember a great rotating starfield in the Atari STe Mental Hangover demo by The Pixel Twins.
Instead of single pixels, you could plot a bob instead. Check this out at 4m21s:
https://www.youtube.com/watch?v=r_ZurYvf_yY

[Neild323]

Oooo thanks peeps!
Will get onto these links later & check em out, hope yr day is a joyable one

[Total Eclipse]

There was a STOS extension purely for generating starfields. I think it was included on a ST Format coverdisk.

Its results were actually quite impressive, and it allowed horizontal and vertical multi-level parallax starfields (as well as in between angles I think). From what I recall, it was only a couple of lines to set up the starfield, just passing a few parameters including the number of stars to display.

It also had an option for zoomer fields as well.

[Neild323]

Hey thanks for that Total Eclipse, I'll have a dig through the ST format discs & look out for it.

& yes, the demo construction kit would be amazing LynXX. I think a while back you'd recommended this & I tried it, but rediscovered that for some reason I'm unable to get the program started. I think its due to perhaps a slight lack of knowledge on my part in the way steem works. I'll really need to come back to that one & figure out why I can't start it up.

I also had a problem learning Stos game creator as I got so far through the manual's guide, I couldn't get any further when it asked for language disk 1, I think maybe theres some fundamental things about steem I'm missing as I'm pretty new to using it with apps. I'd burn it to floppy & use my ST but, it's missing a few keys! Buying x2 fresh STs from a friend soon anyway

but yes, Demo Construction Kit seems like a great way to get my visuals together.

As a back up plan to keep the whole idea moving, not sure if anyones interested but here's some awesome demos & games I found great starfields in:

Venturer Demo
Offbeat (gigastarts screen)
Trip a tron - llamasoft (almost starfield, but nice & controlable)
Hate
Escape - Equinox
my socks are weapons
flipo demo - oxygene (nice wormhole stars)

Eventually it's gonna look very edgy. I was fascinated by 'revenge of the mutant camels' as a kid, which inspires me to make sprites in a similar warped kinda psychedelic way. Should be really good, it's gonna be to a remix of 'operation Thunderbolt', going into another remix of 'cosmic pirates'.

[mlynn1974]

There was a STOS extension purely for generating starfields. I think it was included on a ST Format coverdisk.

Yes this was on STF37A\STF37B. It was written by Lee Upcraft Febuary 1992. It includes an extension for the compiler and the interpreter.

There are 4 commands:
SET STARS 100,t,sx,sy,ex,ey,sc,ec
t=0 for flat stars, t=1 for parallax stars or t=2 for 'zooming' stars
GO STARS x,y,screen
WIPE STARS ON
WIPE STARS OFF
Turns off the automatic clearing process.

It runs quite well and 2 examples are included:
(1) A horizontal starfield and (2) a "3d" zoomer starfield that changes its origin depending on the joystick position.
This is fun to use and good enough for prototypes.
There is no control over the initial positions or speed of individual stars in the array though.

[thomas3]

There are some nice starfields in demos by The Lost Boys.
The maths isn't too difficult and can easily be implemented in STOS.

Any links to good, readable source code for a 3D starfield (in basic or ASM)?

This was always one of those effects where I'm sure I must be missing what the trick is, because the way I'd logically do it would be too slow for a demo screen... unless projections are all precalculated?

[Neild323]

I had a look through the ST format disks & tried 37a out of a few, now I've just given 37b a go, got it!

I was starting to learn STOS the other week & was doing alright, but couldn't complete the user guide after I was asked for the language disk, so theres a lot I'm missing yet, I'm learning on steem too as my atari is missing a few keys & its easier to get started with the moment. So just struggling to run it on stos due a lack of understanding on my part, might need to get the manual out again & give it another go before I can try this.

There might be a lot more I need to understand, but I've got as far as running STOS STARS extension installer V1.0 by Lee Upcraft, but I don't know what to do to get it started. I pressed 1 to install STOS interpreter extension which seemed ok, but when I chose 2 to install the compiler it displayed 'there is no compiler folder on this disk'. I'm just confused as a newbee to stos regards how it works in general.

I think I need to complete the STOS 2.6 guide before I can continue, unless theres something obvious I'm misunderstanding. If I type list it brings up the code for it so I know its loaded ok, I think I'm running the installer & not the program. Might need to get back to this once I've learnt more about Stos I think. Cheers though, a brilliant reference to come back to soon!

[mlynn1974]

I've written an example 2d (horizontal) and 3d starfield in STOS.
It requires Misty and Missing Link for dot, wipe and hardkey commands.
There is a faster version with a 1 plane clear screen and 1 plane dot routine written in ASM. Please see the attachments.

This isn't optimized for speed but might be useful for educational purposes.
It's really cool that Steem can emulate a printer to allow us to print to a file. You can simply dump the STOS listing using LLIST.

3d starfield

Code: Select all

10 curs off : click off : key off : hide : mode 0
20 STARS=100
30 ZDEPTH=256
40 dim X(STARS) : dim Y(STARS) : dim Z(STARS)
50 for N=1 to STARS
60 X(N)=rnd(319)-160
70 Y(N)=rnd(199)-100
80 Z(N)=1+rnd(ZDEPTH)
90 next N
100 logic=back
110 rem ** main loop
120 wash logic,0,0,320,200
130 for N=1 to STARS
140 Z(N)=Z(N)-4
150 if Z(N)<=1 then Z(N)=ZDEPTH
160 X=(X(N)*ZDEPTH)/Z(N)+160
170 Y=(Y(N)*ZDEPTH)/Z(N)+100
180 if X>=0 and X<=319 and Y>=0 and Y<=199 then dot logic,X,Y,1
190 next N
200 if hardkey=57 then goto 230
210 screen swap : wait vbl
220 goto 120
230 default : mouseon : end


[Neild323]

ahh thats really cool of you!
I'll give this a go myself today, getting my head around STOS still but I'm further ahead than I was now, yet still a beginner.
I'm sure Thomas3 will be happy with it

[thomas3]

Ahhhh, thanks! You know, that's how I'd have done it - surely demos must precalc the 3D projections?

I'm back into STOS again at the moment so am gonna have a play with this... when I've finished my 1vbl multidirectional checkerboard, which I've nearly pulled off whoooooop

[mlynn1974]

Ahhhh, thanks! You know, that's how I'd have done it - surely demos must precalc the 3D projections?

I don't think it's necessary to precalc the 3D projections. On the Amiga Paul from DigiTech helped me write a 3D starfield in ASM using integer maths, divs and muls and I got 500 stars at 50Hz. I used the blitter to clear the bitplane though.

On the ST a fast dot routine is possible with the Y-table scanline offset table and power table:
plotpoints
dc.w 32768,16384,8192,4096,2048,1024,512,256,128,64,32,16,8,4,2,1

In The Misty Demos A Globe Called Alice was entirely precalculated and took up about 105kB.
I have the point data for the globe somewhere, but not the equations...

[LynXX]

I fired up DCK on Hatari, what a blast from the past!! Last time I used this was probably 25 years ago on a real ST

Unfortunately DCK is French only, so I annotated a screenshot for you if you want to play with it. Just click on "ETOILES" at the bottom to setup the stars:



After that, make sure you go to the "VALIDATIONS" menu and tick "ETOILES":



And then to view the result, click on "VISU" at the bottom, and click "OUI":



Here's your starfield!

[thomas3]

In The Misty Demos A Globe Called Alice was entirely precalculated and took up about 105kB.
I have the point data for the globe somewhere, but not the equations...

IIRC that was a pure STOS screen, wasn't it? I'm assuming the plot routine was doke-ing directly to screen memory?

[Neild323]

I fired up DCK on Hatari, what a blast from the past!! Last time I used this was probably 25 years ago on a real ST

Hey cheers, & massive extra thanks for annotating it in English! I couldn't figure out why I wasn't able to run it in steem. I burnt DCK to floppy & run it on my Atari. I know I was missing something simple in getting it started - I was running in low res, set to high res & I'm laughing now.
Will have a good play around with it later this eve, at the mo I'm trying to get Maxymiser to burn to floppy, makedisk doesn't seem to work with PRGs but, I'm sure theres a thread on here explaining it.
Looking forward to getting some stars moving about!

[LynXX]

Oh yeah, it doesn't run on low res. The weird thing is that with EmuTOS it just returns to the desktop without any error, whereas with a real TOS it does display a message about the resolution (in French, though!)

[Neild323]

Oh yeah, it doesn't run on low res. The weird thing is that with EmuTOS it just returns to the desktop without any error, whereas with a real TOS it does display a message about the resolution (in French, though!)

Haha, yeah I got part of that message & wondered what I was doing wrong, thought I'd test it on the ST just to be sure I had my settings right in Steem. Good that I now have it to play with on the ST as a result though! Just hope my floppy disks are as good as they once we're

[mlynn1974]

In The Misty Demos A Globe Called Alice was entirely precalculated and took up about 105kB.
I have the point data for the globe somewhere, but not the equations...

IIRC that was a pure STOS screen, wasn't it? I'm assuming the plot routine was doke-ing directly to screen memory?

That's right! Each frame was precalculated and the offset and 16-bit word was stored if not zero. I can't remember the end of frame marker. It was a long time ago.